Pakistani police say five suspected militants arrested during a raid on a house in Punjab province are US nationals wanted by the FBI.
Officials said they were the same men who disappeared from their homes in the US state of Virginia late last month.
Their families reported them missing after finding a farewell video message, showing scenes of war and urging for Muslims to be defended. Police said the men were arrested after offering their services for attacks.
The men hold US passports. Two of them are Pakistani-Americans, while the remaining three are of Eritrean, Ethiopian and Egyptian origin, officials said. US authorities have not yet confirmed the men's identities. The five were arrested earlier this week in the city of Sarghoda, about 190 km (120 miles) south-east of the capital, Islamabad, officials said.
They were detained in a raid on a house belonging to an uncle of one of them, the Pakistani embassy in Washington said.
Dr Usman Anwar, Sarghoda's police chief, said laptops, mobile phones and maps of Pakistani cities were recovered from the property during the operation.
Dr Anwar said the men had been in direct contact with various militant groups in Pakistan since August.
"They were offering their service to carry out attacks, although we don't know what their target was at the moment," he told the BBC.
He said the FBI was in Sarghoda and was examining the evidence retrieved from the scene of the raid. The five men, all students, were reported missing from their homes in northern Virginia by their families in late November.
The families reportedly passed on a video to members of the US Council on American-Islamic Relations (Cair).
Nihad Awad, the council's executive director, said the video appeared to be "like a farewell".
"One person appeared in that video and they made references to the ongoing conflict in the world, and that young Muslims have to do something," Mr Awad told Associated Press news agency.
He said the video had made him "uncomfortable" and he had advised the men's families to contact the FBI.
The BBC's Syed Shoaib Hasan in Islamabad says that while it is not unusual for foreigners with suspected hardline Islamic links to be arrested in Pakistan, it is unusual for Americans who may be wanted by the FBI to be detained.